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Need opinions re: RV7 IO390 starter button on stick?

Desert Rat

Well Known Member
Hey guys.

I'm seriously considering putting a starter button on the pilot stick grip.

For those of you with a IO390 in an RV7, how necessary/convenient is it to have the stick back during start? Yeah, I know that it's always good form to do that, but is it a case where you're gonna immediately nose plant if that stick slips out from between your knees on an oopsie 1200 rpm hot start?

I've always been a proponent of the KISS principle, especially with gadgets, but I can see some real value here in this case, and I don't see why I couldn't run one in parallel with a panel mount push button and a starter arm safety somewhere. to prevent inadvertent button pushing.

I'm not at that point yet, but just starting to look at electrical planning and I'm looking for opinions and experience form those who have gone before.
 
My .02 -- keep it on the panel/dash; key or button.

The last thing you need/want is to inadvertently smash the start button on the stick while maneuvering...
 
Easy way to break teeth on starter ring with inadvertent touch.

Thinking the logic behind buttons on stick are ; often used, need quick access. Starter button there, falls in neither categories. Another opinion.
 
Starter on stick

Terry,

Nothing wrong with that, especially hot starting a tail dragger on a windy day. Definitely a good idea to have your hand on the stick during start. You could easily have one of the buttons on the stick designated for starting but you should consider running through a separate “consent” switch so you don’t inadvertently hit the starter with the engine running. Switch on for start, engage starter, switch off after start.
 
I use an Infinity stick grip. The starter button is located top right on a right handed stick, so I must lift my thumb up and over to reach it. Inadvertent activation is unlikely.

Moreover, my mags are activated by two DPDT toggle switches. As the left mag is impulse, the left mag must be on and the right off to start. The left side of the switches handle the mag grounding/un-grounding.

The right side of the switch handles the logic for engaging the starter. To start, the left mag must be in the full up position and the right switch full down to engage the starter with the left mag un-grounded. After start, the right mag switch goes full up to un-ground it and the starter relay engagement path is deactivated.

Also, with the left mag in the middle position and the right mag in the down (off) position I can engage the starter with both mags grounded. This is a maintenance mode.

In the extremely unlikely event that I needed to "air start" with a stopped prop I would have to flip the right mag switch to off.

Don
 
The short answer - don’t do this.

I put the start button on the Infinity Grip on my first RV (adding the in line relay as the starter solenoid draws too much current for the stick button). During the first few flights I inadvertently hit the start button twice with the engine running. Luckily the damage to the starter ring was minor.

I use the nice start button from Stein (with bezel), mounted either on the bottom left of the panel apron (RV-10) or on the side breaker panel (RV-8).
https://www.steinair.com/product-category/switches/start/

Carl
 
This should answer your question!

I am NOT a proponent of starter buttons on the stick.

It should, but unfortunately it doesn't. If that was an iron clad rule, none of us would have moved up to fuel injection or constant speed props, I for sure wouldn't have ordered an engine with 2 Pmags, and you wouldn't be doing glass panel upgrades. At some point, KISS has to make way during the cost benefit analysis :)

In this case, I know how easy it is to run out of hands on a temperamental fuel injected hot start and just considering my options.

Guys- I'm not some gadget enamored 18 year old. I understand all the potential down side here, including the safety aspects in the shop. I'm typically not a fan of a bunch of junk on the stick either. I can see a potential benefit here, but this is not a hill I'm willing to die on either way.

Like I said, all opinions welcome, but mostly I'm looking for some feedback from the guys who have put IO390s in an RV7. Do you have a stick start button, if not is it a big deal to keep the old girl from face planting if the throttle is a little too robust during the start sequence?
 
It's your airplane. Do what you want. A particular engine and/or airplane has nothing to do with it.

The stick should be held full back during start on ALL small airplanes.
 
Thanks guys.

Mel- I always appreciate your candor and hope you don't think I'm being intentionally argumentative. just weighing my options here.
 
Start button on a stick

I have had my start button on my infinity grip for over 11 years now. I have had zero problems with this setup. We have in my group of guys that have RVs over 7 planes with it. I have flaps on the stick also, and love it.
 
I’ve had the start sw both ways and definitely prefer it on the stick with a starter arming sw on the panel. With fuel injection, I have to use the left hand on mixture. Putting button on the stick makes it easy to hold up elevator while starting and the arming sw eliminates activating starter while engine is running, just as long as you remember to sw to off after start.
 
I decided to go ahead and wire it up to the pilot stick since I didn’t want to have to go back in later. I have a terminal block mounted below the seat area where I tie the common stick signals together. I ran the 12v that is required for the start button to there. Then if I want to disable the function later I’ll just disconnect it there.

I have an Infinity stick grip. I used the lowest switch which is difficult for me to reach for the starter switch. That way I’m not as likely to bump it.

I was on the fence about the stick start function but I think this option works pretty well.
 
Bad ideas create bad results

OK this is one way to have a bad day. If you've ever seen what a starter looks like after it was hooked up to an engine turning 3,000. You would NEVER do this. Seen a few. Ya I know it is only a momentary switch. They can fail.
Not my idea of a good idea.
Just my three cents worth
Art
 
OK this is one way to have a bad day. If you've ever seen what a starter looks like after it was hooked up to an engine turning 3,000. You would NEVER do this. Seen a few. Ya I know it is only a momentary switch. They can fail.
Not my idea of a good idea.
Just my three cents worth
Art

Or better yet after someone gets whacked with the prop when it cranks accidently...
 
Hey guys.

I'm seriously considering putting a starter button on the pilot stick grip.

For those of you with a IO390 in an RV7, how necessary/convenient is it to have the stick back during start? Yeah, I know that it's always good form to do that, but is it a case where you're gonna immediately nose plant if that stick slips out from between your knees on an oopsie 1200 rpm hot start?

I've always been a proponent of the KISS principle, especially with gadgets, but I can see some real value here in this case, and I don't see why I couldn't run one in parallel with a panel mount push button and a starter arm safety somewhere. to prevent inadvertent button pushing.

I'm not at that point yet, but just starting to look at electrical planning and I'm looking for opinions and experience form those who have gone before.

Terry, I can't offer an opinion on the necessity of holding the stick back, but I sympathise with your thinking, and desire to simplify. I eventually went with a start button mounted dead centre of the panel above the prop control. In this position I can push the start button with my hand on either the throttle or mixture. I really like this, and hot starts (IO360-M1B) have been very simple, my right hand can do everything necessary while the left just holds the stick back. I also wired it so the start button is only enabled if the mags are correctly confgured and a start enable switch is on, just in case someone mistakes it for a TOGA button or something.
 
The start arm switch is hidden. The "starter armed" warning light (a flashing LED) ensures I don't forget to turn it off. The relay means no significant current at tiny grip switch.

Right hand, stick back and start command. Left hand, throttle, mixture, purge valve.

About 1000 hours now.
.
 

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Why put an extra switch on the stick grip for something you are only going to use once every flight. I don't understand why builders incorporate so many functions on the stick. It would seem that PTT and trim would suffice.
 
Jake, I tend to agree with you. Not much driver for it with an -A model, or a carbed 360. Other applications make more sense.

Circa 2007, there were very few 390/metal Hartzell RV-8s. I knew the inflight CG could easily reach the forward limit, but I had no idea if, or how easily, a throttle burst might raise the tail with the brakes locked. So, always stick back for cranking, per best practice.

Constant flow injection adds some additional hand manipulation. For example, the average quick turn is mixture ICO to stop, then ease mixture forward slowly while cranking, a mixture sweep lean to rich. If flooded, the classic "flood it, WOT to crank" is a rich to lean sweep, with the potential for a bunch of RPM if fumbled.

Either way, wiring crank on the grip was easier than growing a third hand.
 
The start arm switch is hidden. The "starter armed" warning light (a flashing LED) ensures I don't forget to turn it off. The relay means no significant current at tiny grip switch.

Right hand, stick back and start command. Left hand, throttle, mixture, purge valve.

About 1000 hours now.
.

That is the same way I wired mine. Also have the PTT button on the throttle. RV-8.
 
I see 1 excellent exception to comments so far re starter switch on the stick - ie when using the VPX bus system. Am really surprised no one has mentioned this before as there are a lot of VPX systems installed now. Personally the only reason I see the need for a starter on the stick is with tail draggers - absolutely no need to with nose wheel aircraft.
VPX - when the revs are above 500 rpm the starter circuit is disabled therefore accidentally touching the starter button will not activate the starter;)
 
I'm curious how much current is required for the starter solenoid. I'm still not committed to having the switch yet either. I do think if you need a panel disable switch and another relay that maybe its not worth having a stick switch.
 
Yes you will need a relay. Make sure you put a clamping diode across it or you will run the risk of burning out the switch on your stick.
 
I suspect this 3.5amps in holding current. Surge latch current might be a lot higher.

The standard switch (not top hat) on an Infinity Grip is rated at 6 amps. I would not use that as a a basis to skip using the grip switch to operate a simple, 100ma relay that would then power the starter solenoid.

Pitted switch contacts need be avoided.

Carl
 
Yes I agree this is the holding current, I could haul out the O Scope with the current probe and get the peak but it is not worth the hassle. <G>
 
No stick starter switch on the stick here…

I think this is much ado about nothing.

On my -8, it’s really easy to hold the stick back between my legs during engine start. To me, this is much easier and simpler than adding a bunch of extra wires, relays and disable switches to add a starter button to the stick!

Keep it simple!

Skylor

p.s. You’ll thank me if you ever have to troubleshoot an intermittent starter issue…
 
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Infinity Stick Grip with engine start button

I have Infinity stick grips with switches for the functions engine start, trim, flaps, AP con/disc, fuel pump and PTT. They works perfect! For safety reasons the engine start button needs to be cleared or activated pressing a separate button switch for 2 or more seconds. This switch is located near the trottle knob and has an integrated led that flashes while the the engine start button on the grip is „hot". The engine start button will remain active until it was released or the clearance/activation switch was pressed for two seconds or more. I implemented this solution using a small programmable relay Eaton easy 500. The flap switch on the grip just uses the G3X airspeed limit protection function and in my configuration it is only activated below 87kts.
 
Clearly two different camps here. Whatever level of Gee Whiz you choose to build (low or high, for your own good reasons), just be sure you have a way to avoid blowing the starter or ring gear off your motor by inadvertently touching the wrong button.

And keep in mind that without proficiency (training and perfect practice), all the little details of function become a whole 'nother ball O bees when the stuff hits the fan or you can't see due to smoke or injury.

Just sayin' ... be careful out there.

Cheers
 
Clearly two different camps here. Whatever level of Gee Whiz you choose to build (low or high, for your own good reasons), just be sure you have a way to avoid blowing the starter or ring gear off your motor by inadvertently touching the wrong button.

And keep in mind that without proficiency (training and perfect practice), all the little details of function become a whole 'nother ball O bees when the stuff hits the fan or you can't see due to smoke or injury.

Just sayin' ... be careful out there.

Cheers

I am in the 'starter on the stick' camp in my Harmon Rocket. I use the existing master switch to enable the button on the stick as shown on this diagram: http://www.vx-aviation.com/sprocket/photos/panel_elec/schematics-2/MASTER.pdf

Sarting is done with the master in the ALT position. After start, switching the master to ON disables the starter.

V
 
On my -8, it’s really easy to hold the stick back between my legs during engine start.

When you turn into an old man and your legs get skinny, you'll find your knobby knees collide before your thighs come together ;)
 
Not where I thought this thread would go . . .

Surprising (to me) that the stick-start option has foundation in a solid safety aspect and the added unintended-start failure mode can be (should be) mitigated by design.

Needing 4 hands for the hot start juggling act in my -7 leaves the stick low on the list of being handled. We know, and have seen the video, of a full flap RV8 nose over in an airshow line-up for the smoke show. It can happen.
 
BillL - I’ve seen that happen here once, engine had a bulk strip & prop replaced. Then he DID IT AGAIN ! Stupid is, stupid does.
The nose over at start is one of the idiosyncrasies of a tail dragger IF you are not paying attention :rolleyes: NOT trying to start a war over this - just pointing out the obvious for most of us.;)
 
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I'm in the start switch on the stick camp for taildraggers. I have the infinity stick grips and I configured it where 2 buttons need to be pressed simultaneously for start. It's the pinky and a top switch that is an awkward move that I can't imagine pressing both accidentally.
 
My RV-8 came with an Infinity grip with all the buttons. Start, flaps, autopilot disconnect, PTT. I really didn't like the looks of it and thought it was overdone and frankly silly. Then I started using it. The start button has become my favorite item on the stick. It really makes things easy. The system has an "arming" switch on the panel for the stick start button and the standard key switch can also be used stand-alone for start. I used the key switch at first but transitioned to the stick start button after a while. Then a couple of buddies and myself went out to Prattville, AL to buy an RV-4 with a hot-rod IO-360 on it. The first guy that started it almost got the prop and I can't figure out to today how he didn't. Quite impressionable how fast it can happen. I haven't used the key switch since. I honestly don't remember even how I got the key start to work using the mixture "sweep" method requiring one whole hand while the other holds the stick back.

As an aside the flap switch on the stick is my second favorite, even more so than the PTT. Nothing like planting the mains and with the flick of a thumb have the flaps start retracting.
 
Surprising (to me) that the stick-start option has foundation in a solid safety aspect and the added unintended-start failure mode can be (should be) mitigated by design.

Needing 4 hands for the hot start juggling act in my -7 leaves the stick low on the list of being handled. We know, and have seen the video, of a full flap RV8 nose over in an airshow line-up for the smoke show. It can happen.

Agree.
Start on stick here as well. With a disable DPST switch on panel and an "ignition enabled" annunciation via discrete on the EFIS
Simple and idiot proof.
The way to go for an injected TD IMHO.
 
When you turn into an old man and your legs get skinny, you'll find your knobby knees collide before your thighs come together ;)
Sounds like you skipped leg day at the gym. Or don't eat enough blueberry pancakes!
 
I like Vern's idea of using the master switch alt position as an enable for the stick starter. No extra switch is required then. I just connect it up to the unused terminal on the existing switch.

After reading more about the starter contactor required current I think the infinity switch by itself isn't a high enough current rating for me to feel comfortable. I added the relay and Vern's power connection to my schematic.
 
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